This invention relates to loud speaker baffles and baffle assemblies, particularly those which are mounted at or below floor level. Prior U.S. Pat. No. 3,108,653, the disclosure of which is incorporated by reference herein, discloses a speaker baffle assembly which may be mounted in a floor. The speaker is connected to an imperforate portion of a floor baffle. The speaker directs the sounds downwardly to a sound deflecting nose cone which turns it 180.degree. and directs it back through a perforate portion of the floor baffle. The nose cone is formed as an integral part of the speaker enclosure which is mounted in a hole in the floor.
Other floor or ground level mounted speakers are disclosed in German Pat. No. 721,732 of 1942 and in "Ground Loud Speakers," by David Scott, in the October, 1949 issue of Audio Engineering, pages 18 and 19. Both U.S. Pat. No. 3,108,653 and German Pat. No. 721,732 disclose structures which require a floor grill having an imperforate portion, which protects the speaker from damage from water or objects dropped into the assembly. The device disclosed in Audio Engineering uses a very expensive water proof assembly which can be operated under water. Water proof assemblies are, of course, expensive. Particularly where large numbers of the speakers are required, the cost of water proof equipment can be prohibitive. It is desirable to provide an inexpensive ground level or floor level loud speaker mounting system which provides adequate sound at an economical capital investment.
Applicant's assembly utilizes economical speaker components, yet protects them from damage or destruction caused by water or debris, when placed in a floor or ground level installation. In addition, applicant's structure is easily removable. The speaker assembly can be serviced from above the floor level without removing the surrounding enclosure from the floor. A floor grill may be used which is open to the maximum extent consistent with strength. The grill does not require imperforate portions to protect the speaker assembly beneath, thus allowing a wider distribution of sound. The speaker assembly itself is provided with a self-contained protective can which protects the speaker assembly from damage from debris and water.
The protective cover is preferably provided with relieved areas which allow the back pressure behind the speaker to be relieved. The relieved areas also transmit more of the sound generated by the speaker allowing the sound to fill a greater volume around the speaker. The speaker assembly is provided with a sound deflecting nose cone which deflects the sound from the speaker and reverses the direction 180.degree. so the sound passes out of the enclosure into the space around the speaker. Preferably a wide angle deflection nose cone is used and it is placed close to the speaker so that a greater volume filling effect is achieved for the sound. Preferably, the speaker unit is not attached to the floor enclosure or the floor grill at all, except by resting on the bottom of the enclosure. A sound deadening means, such as a jute mat, is provided on the bottom of the enclosure to absorb any resonant vibration and to absorb minor amounts of moisture that may fall into the enclosure.
The resulting structure is a loud speaker assembly, using inexpensive components, which can be mounted beneath a floor surface in such a manner that sound is transmitted to above the floor level and fills the space around the speaker. The speaker assembly is protected from damage due to water or objects falling into the assembly from above the floor. The unit can be simply and inexpensively mounted in a hole in the floor, the entire enclosure and speaker assembly can be installed as a unit or the speaker assembly itself can be replaced or installed in a previously mounted enclosure. The speaker unit is completely beneath the floor level so that the assembly blends uniformly with the floor surface. The speaker assembly provides a reliable sound system and quality sound production.